Lipid anchoring of Arabidopsis phototropin 1 to assess the functional significance of receptor internalization: should I stay or should I go?
Lipid anchoring of Arabidopsis phototropin 1 to assess the functional significance of receptor internalization: should I stay or should I go?
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DOI：
10.1111/nph.13299
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发表时间：
2015-05-01
期刊：
影响因子：
9.4
通讯作者：
Fankhauser, Christian
中科院分区：
文献类型：
--
作者：
Preuten, Tobias;Blackwood, Lisa;Fankhauser, Christian
向光性 1 (phot1) 蓝光受体介导许多适应性反应，包括向光性，通常有助于优化光合作用能力。 Phot1 是一种质膜相关蛋白，但在辐射后，一部分会内化到细胞质中。尽管这种现象已被报道十多年，但其生物学意义仍然难以捉摸。在这里，我们使用遗传学方法重新审视有关受体内化功能重要性的普遍假设。表达永久固定在质膜上的 phot1 脂质化版本的转基因植物被用来分析内化对受体周转、向光性和其他 phot1 介导的反应的影响。肉豆蔻酰化和法呢基化有效地阻止了 phot1 内化。两种修饰的光感受器被发现在拟南芥中完全发挥作用，挽救了向光性和所有其他测试的 phot1 介导的反应。光介导的 phot1 转换发生在天然受体中。此外，我们的工作没有提供任何证据证明 phot1 内化在向光性过程中受体信号传导减弱中的作用。我们的结果表明 phot1 信号传导是在质膜上启动的。他们还表明，phot1 释放到胞质溶胶中与受体更新或脱敏无关。
The phototropin 1 (phot1) blue light receptor mediates a number of adaptive responses, including phototropism, that generally serve to optimize photosynthetic capacity. Phot1 is a plasma membrane-associated protein, but upon irradiation, a fraction is internalized into the cytoplasm. Although this phenomenon has been reported for more than a decade, its biological significance remains elusive. Here, we use a genetic approach to revisit the prevalent hypotheses regarding the functional importance of receptor internalization. Transgenic plants expressing lipidated versions of phot1 that are permanently anchored to the plasma membrane were used to analyse the effect of internalization on receptor turnover, phototropism and other phot1-mediated responses. Myristoylation and farnesylation effectively prevented phot1 internalization. Both modified photoreceptors were found to be fully functional in Arabidopsis, rescuing phototropism and all other phot1-mediated responses tested. Light-mediated phot1 turnover occurred as in the native receptor. Furthermore, our work does not provide any evidence of a role of phot1 internalization in the attenuation of receptor signalling during phototropism. Our results demonstrate that phot1 signalling is initiated at the plasma membrane. They furthermore indicate that release of phot1 into the cytosol is not linked to receptor turnover or desensitization.